refactor(metadata-protocol): move the runtime authoring gate and the restored-body doors out of protocol.ts into protocol-authoring-gate.ts

Five ObjectStackProtocolImplementation methods (runAuthoringGate,
assertRuntimeAuthoringRules and the restored-body derivation, writer and
save-door refusal) move unedited into a new module under the shape-B host
pattern. The objects-tolerance spelling pin reads both files, since the
collection pair it counts moved with assertRuntimeAuthoringRules.

Co-Authored-By: Claude <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01J8pUyVs5eas1AjMdReJM7C

Author: claude